A Comparative Analysis of Serum IgG4 Levels in Patients With IgG4-Related Disease and Other Disorders

High levels of IgG4 were observed in IgG4-RD. However, a diagnosis of IgG4 disease can not only be dependent on the detection of elevated serum IgG4 levels but also may need clinical manifestations, serology, histopathology and other comprehensive information for verification.